I'm trying to catch the natural submission of this form and submit it with AJAX instead.
<form name="input_form" class="input_form" method="post" action="input?nmap_xml" enctype="multipart/form-data">
    <input name="input_file" type="file">
    <input name="blah" type="text">
    <input value="Submit" name="submit" type="submit">
</form>
Here is how I'm AJAX posting the form:
$(document).on('submit', '.input_form', function(e){
    $.ajax({  
        type: "POST",  
        url: $(this).attr('action'),
        data: $(this).serialize(),
        success: function() {  
            alert();
        }  
    });
    e.preventDefault();
    e.stopPropagation();
});
It "works" except for the fact that the file input is not passed (not even the key name is passed, it's just ignored). The blah text input is passed fine.
EDIT: The question this is supposedly a duplicate does not provide an answer to the question I am asking, although admittedly the title suggest it does.
A hint to a possible answer is giving in the very last comment of the answer, as pointed by user ahrim, namely to use enctype="form/multipart". Unfortunately this doesn't work and my problem is exactly the same with that enctype. 
